Step 1

In a small saucepan, bring the milk to a simmer. In a medium saucepan, melt the butter. Add the flour and whisk over moderate heat for 1 minute. Gradually whisk in the hot milk and bring to a boil. Cook, whisking, until thickened, about 5 minutes. Remove the pan from the heat and whisk in both cheeses until melted. Stir in the nutmeg and hot sauce and season with salt and pepper.

Step 2

Preheat the oven to 425°. Arrange the bacon on a rack set over a baking sheet. Cook until golden and crisp, about 30 minutes.

Step 3

Preheat the broiler. Arrange the tomato slices on a baking sheet, drizzle with the oil and season with salt and pepper. Broil 6 inches from the heat until lightly charred, 1 to 2 minutes per side; keep warm.

Step 4

Arrange the bread on a foil-lined baking sheet and spread each slice with 1/2 tablespoon of the butter; season with salt and pepper. Broil until lightly toasted, about 2 minutes. Flip the bread and toast for 1 minute. Top each toast with some turkey and a slice of tomato. Spoon the sauce on top and sprinkle on both cheeses. Broil until the cheese is melted and golden brown, 2 to 3 minutes. Transfer the sandwiches to plates and top with the bacon. Garnish with chopped chives and parsley and serve hot.